Machine tool



oct. 2s, 1941. G. K. MCKE .2,260,327

MACHINE TOOL Filed Aug. 3l, 1959 7 Sheets-Sheet 1 lasA 241 l ,'nz Z7 ,nlo u@ /Lfl '..m

1N VENTOR.

Geo/ref l( Mc K Ee Oct. 28, 1941'. G. K. MCKEE 2,260,327

MAGHINEL TooL Filed Aug. 51, 1959 vsheets-.sneet 2 0a. 28, 1941. G. K.MC'KEE MACHINE i TooL Filed Aug. 3l, 1939 Y 7 Sheets-Sheet 4 Oct. 28,1941'.

G. K. MCKEE MACHINE -TOOL '7 Sheets-Sheet 5 Zio Filed Aug. 31, 1959 Oct.28, 1941.

G. K. MCKEE MACHINE TOOL Filed Aug. 51, 1939 i DI 292 -2sq zqa 48 2mINVENTOR. G50/mf A. McrEE /w ATTORNEY.

Oct. 28, 1941. ,Q K MCKEE 2,260,327

MACHINEA TOOL Filed Aug. 3l, 1959 '7 Sheets-Sheet 7 INVENTOR. Cso/eas K.Mauss v ATTORNEY.

Patented Oct. 28, 1941 MACHINE TOOL George K. McKee, Cincinnati. Ohio,asslgnor to The Avey Drilling Machine Company, Covington, Ky., acorporation of Ohio Application August 3i, 1939, Serial No. 292,850

19 Claims.

This invention relates to improvements in machine tools, andparticularly to improvements in drilling machines and the controltherefor.

In drilling machines, particularly those for drilling long holes, suchfor example as the oil holes for the bearings of crank shafts as used ininternal combustion enginesY and the like, it is necessary toperiodically clean the hole of chips to prevent binding of the drill, aswell as cool the drill. In the past, this periodic withdrawal of thedrill from the hole for chip clearance and drill cooling has beeneffected at comparatively close intervals, that is, after each fractionof an inch of drilling or after each given comparatively short time. Ithas been found that such a mechanism frequently consumes more time thanis absolutely'necessary, that is, the drilling time is generally tooshort, resulting in a loss of time. Frequently, however, by increasingthis drilling time, trouble is encountered in that hard spots are hereand there encountered which causes the drill to stick, and, whendrilling at the rate of feed, results in broken drills.

A mechanism operating in accordance with the above is disclosed in thepending application of George K. McKee and Charles E. Bernitt, SerialNo. 112,724, filed November 25, 1936, for Machine tools. now .UnitedStates Patent No. 2,183,297, and 'on which the mechanism of thisapplication is an improvement. The present mechanism contemplates theprovision of control means which will withdraw the drill from the holein the event of sticking or undue resistance to drill movement, and atthe same time effect this withdrawal at definite intervals for chipclearance and the like. By the mechanism of this invention, theheretoforeknown advantages of a step or deep hole drilling machine areretained without the unnecessary loss of time due to unneces'- sarilyfrequent withdrawals of the tool from the Work, thereby cutting down onthe idl'e times of machine as heretofore used.

It is therefore an object of thisinvention to provide a deep hole orstep drilling machine which will withdraw the tool or drill from thehole -at definite intervals or steps, and at the same time withdraw thedrill when the` pressure thereon becomes excessive. It is another objectof the present invention to provide a drilling machine of the classabove referred to in which the torque or resistance to rotation of thedrill due to interference in its feed causes its'withdrawal.

It is a still further object of this invention to provide a drillingmachine of the class above referred to in which the torque on the drillgoverns the length of feed Stroke of the drill, and when such torqueexceeds a safe limit, causes a withdrawal of the drill.

It is also an object of this invention to provide a machine tool ordrilling machine to accomplish d the above objects, which is economicalto manufacture and comparatively simple in its operation.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification considered inconjunction with the accompanying drawings forming a part thereof, andit is to be understood that any modifications may be made in the exactembodying the improvements oi this invention.

Fig. 2 is a side elevation oi the improved drilling machine as seen fromthe right hand side of Fig. 1.

Fig. 3 is ahorizontal, sectional view through the spindle drive taken online 3--3 on-Fig. 2.

Fig. 4'is an enlarged view of the spindle drive, partly in section andpartly in elevation, as seen from line 4-4 on Fig. 3.

Fig. 5 is a sectional view taken on line 5-5 of Fig. 4.

Fig. 6 is a view similar to Fig. 3 showing a slight modification in thespindle drive.

Fig. 7 is a view similar to Fig. 4, partly in elevation and partly insection, as seen from line 1-1 on Fig. 6. l

Fig. 8 is an enlarged side elevational view of the tooling head.

Fig. 9 is a top plan view of the tooling head as illustrated in Fig. 8.

Fig. 10 is an enlarged vertical sectional view through the spindlecarrier andr its feed mechanism, taken on line I 0-I0 on Fig. 1.

Fig. 1l is a horizontal sectional view through the tooling head, takenon line Il-i'l on Fig. 8.

Fig. 12 is a vertical sectional view through the tool head andillustrating the main control valve, taken on linev |2-i2 on Fig. 9.

Fig. 13 is a view similar to Fig. 12', taken in a Ipli-ang ahead of thatof Fig. 12 on line l3-I3 on Fig. 14 is a fragmentary sectional viewthrough the feed determining valve, taken on line lI-I4 on Fig. 9.

Fig. 15 is a fragmentary sectional view, taken at right angles to Fig.13, on line lli-lof said Fig, 13.

Fig. 16 is a fragmentary, transverse, sectional view, taken on lineI8`I6 on Fig. 13.

Fig. 17 is an enlarged, horizontal, fragmentary, sectional view througha portion of the drilling head as seen from line I'l-I'l on Fig. 8.

Fig. 18 is an enlarged, fragmentary, vertical, sectional view throughparts of the drilling head, as seen from line |8|8 on Fig. 8.

Fig. 19 is an enlarged, fragmentary view illus-` trating certain of thecontrol dogs. partly in Fig. 20 is an enlarged, fragmentary, vertical,

sectional view, partly in section and partly in elevation, as seen fromline 20-20 on Fig. 8.

Fig. 21 is an enlarged fragmentary, horizontal,

sectional view, taken on line 2I-2I on Fig. 8.

on Fig. 8.

Fig. 24 is a diagrammatic view, depicting the complete hydraulic andelectrical circuits utilized in effecting and controlling themovementsof the drill or tool carrier. Throughout the several views of thedrawings,

similar reference characters are employed to'denote the same or similarparts.

`section and partly in elevation, as seen on line l IB-l 9 on F18. 8.

Asl was noted above, this invention pertainsprimarily to controlling adrill for performing step or deep hole drilling operations, that is, amachine in which the tool or drill is advanced `at a rapid rate to thework, fed at a slow rate through a part of the work and then retracted,

` followed by a rapid advance of the drill or tool to fthe point whereit was previously withdrawn for Ia second short drilling step whereuponreversal again takes place. I'his cycle of operation is repeated untilthe work is completely tooled or drilled. Asxwas noted above, thepurpose of this type of a control mechanism is to permit the clearing ofchips from the holes so that they do znot interfere with the rotation oroperation of the drill or tool cooling. In the case of drilling oilholes in crank shafts, this is very essential since such drills are ofcomparatively small diameter and will not stand a great amount of torqueon the drill but might interfere with the `proper operation of thedrill, thereby causing `same to beco'me excessively hot, and means aretherefore provided supplementary to the torque icontrol means forperiodically withdrawing the drill from the hole to provide for lcoolingof the drill.

The machine disclosed in the drawings is a single spindle machine, thatis, a machine for drilling one hole at a time. It should be noted,

. however, that a multiple machine may, and in fact has been, producedin which a 'plurality of drilling heads were employed, therebysimultaneously drilling a comparatively large number of holes, such asthe oil holes for all of the bearings of a crank shaft as used in amultiple cylinder internal combustion engine.

Specifically, the machine shownin the draw-'- ings comprises a base 2,5,from which rises a l standard 26 having formed vertically of its frontface a dovetail `guide 21 having a work supporting table 28. Anysuitable means (not shown) 4may be provided for adjusting the worktable` 28 relative to the guide 21 and for clamping the table inposition. Mounted on the upper end of the `2 v Y Y 9,200,827 i arstandard 2| is a column 20 terminating at yits upper end in a housingl0 for the spindle bearings and like mechanism.

The column 28. at its' upper rear end. is prol2. Projecting from themotor 22 is the motor shaft 22 which projects into a hollow cover cap v24 secured to the housing 30. The motor shaft 23 has keyed or otherwisesecured to it a pulley 85 for a belt 2B. The belt I8 is in turn extendedaround the spindle pulley 31, keyed or otherwise secured to a drivingsleeve 3B. The sleeve 2 8 is journaled in an anti-friction bearing 89and is provided interiorly thereof with suitable driving keys mounted insplines in a spindle 40.

The spindle 40 is mounted for rotation at its lower end in a quill 4I,disposed for axial adjustment in a bore in a tool carrier 42. The upperend of the tool carrier 4| carries an anti-friction bearing 43 for thespindle 40. The lower extremity of the spindle 40 is provided with theusual chuck 44 for the drill or other tool.

'I'he spindle 40 is axially adjustable relative to the carrier 42 bymeans of a rack pinion 45 carried by a shaft 48 rotatably journaled inthe carrier 42. The rack pinion 4B meshes with a rack 41 formed integralwith or secured to the quill 4l. In order to rotate the pinion 45, itsshaft 4B projects beyond the forward side of the carrier 42 and hassecured thereto a knob or the like 48. The lower end of the carrier issplit, and on each side thereof are lugs or ears 4l and lill,respectively provided with a tapped and a plane perforation receiving aclamping stud Il. This clamping stud draws the portions of the carrieron each side of the split 52 toward one another and thereby clamps thequill in adjusted positions.

The spindle carrier, and therefore the parts carried thereby, areactuated by hydraulic means toward and from the work, which means, as

shown in Fig. 10, comprises a rearwardly projecting lug 53 on thecarrier 42 and having a perforation therein receiving the lower reducedend 54 of a piston rod. 55. The piston rod 55 has secured to its upperend a piston 68 movable through a cylinder B1 secured in a bore in thetool head' 58.

In order to prevent loss of fluid and pressure around the piston rod at,its lower end, use is made of a suitable packed joint $9 carried by thelower cylinder head 60. The upper end of the cylinder 51 is likewisesuitably closed by a head 8|. 4

The spindle carrier 42 is guided in its movement relative to the toolhead 58 by means of `a dove-tailed guide 82 received in acorrespondingly shaped guide-way 62 with a gib 84 between one side ofthe guide and the guide-way. The tool head 58 is provided in its rearside with a dovetailed guide-way 85 receiving a correspondingly shapedguide 68 formed on the forward face of the column 29. A gib B'I isdisposed in the guideway 65 between one side of the guide tongue 66 andthe guide-way 65 for clamping the head in position on the said column29.

reference is now to be had, and the various valve and control means willbe described in detail with reference to their structural illustrationsin their other drawings as they are encountered in a cornplete cycle ofoperation of the machine. As shown in Fig. 24. use is made of a tank orsump I8. which may be independent of the machine though preferably isformed in some part of the bed, such as the base 25 and lower portion ofthe stand 25. Mounted above the tank or sump 88 is a constantly rotatingpressure circulating pump Y89v having its intake or suction sideconnected by a pipe with the sump or tank. The discharge side of thepump has extending therefrom the pressure pipe or conduit 1|,terminating in the main control mechanism indicated in general in Fig.24 by the reference numeral 12 The pressure pipe or conduit 1| hasconnected therewith a branch pipe or conduit 13 which terminates in thesump or tank 88, and has intermediate its ends an adjustable reliefvalve 14. The relief valve 14 determines the actuating pressure in thesystem.

The main control valve 12, structurally villustrated in Fig. 12,comprises a valve block secured to the inner face of a plate 15 whichcloses the open right hand end of the tool head 58, as seen in Fig. l.Pressed into a suitable bore in the valve block 15 is a valve sleeve 11having formed therethrough a plurality of sets of radial ports 18, 19,80. 8|. 82 and 83, each set of ports being encircled by a similar groove84 formed in the exterior of the sleeve 11. Disposed in the bore of thevalve sleeve 11 is a spool type valve member 85 provided with reducedportions or cannelures 38, 81 and 88 adapted in different positions ofadjustment to connect the several sets of ports in the valve sleeve 11.

The valve 85 has four operative positions, and

in order to `determine these positions, it has projecting therefrom astem 89 provided with V- shaped notches 80 co-operating with a springpressed detent 9| carried by a valve block 92. The valve block 82,similar to the valve block 15, is secured to the inner face of the plate18, and therefore projects into the interior of the tool head 58. The`position of the valve illustrated in the drawings is the neutral orstop position, and the valve has a position to the right of that shownin Fig. 24, or below that shown in Fig. 12, which is the retractingposition. In order to limit the movement of the valve to the right inFig. 24, and downwardly in Fig. 12, use is made of a stop screw 93carried by the valve block 92 in alignment with the valve stem 89. Athird position oi' the valve 35 is to the left of that shown in Fig. 24and upwardly of that shown in Fig. l2, which is the slow feed positionto cause the tool to feed slowly through the work while a cut is beingeffected. The fourth position of the valve is to the extreme left inFig. 24. and extreme-upper position in Fig. l2, which is the rapiddownward position to cause a rapid approachv of the tool to the work.This fourth position is finally determined by a stop screw 94 threadedinto the upper wall of the tool head 58.

As seen in Fig. 24, the radial ports 19 and 8| have respectivelyconnected with them one end of pip'esor conduits 95 and 98 whichrespectively terminate at ports located at upper and lower ends of thepiston cylinder 51. The ports 80 have connected therewith the upper endof the main pressure pipe or conduit 1|, while the ports 18 and 83 haveconnected therewith pipes or conduits 91 and 88 which terminate in thesump or tank 88, and are therefore the return lines for the system forth'e main control valve. The remaining set of ports 82 of the pistonsleeve 11 have connected therewith one end oi' a pipe or conduit 99which terminates in a balance valve mechanism, indicated in general inFig. 24 by the reference numeral |00, and which-will be described indetail later.A

At thecommencement of a tooling cycle. the valve 85 is manually shiftedby means of a lever |0i, see Fig. l1, which is keyed or otherwisesecured to the outer projecting end of a shaft |02 oscillatablyjournaled in a bushing |03 carried by the toolI head cover plate 18. Theinner projecting end of the shaft |02 has keyed or.

tial shifting of the valve member 85 is to the extreme left in Fig. 24and extreme upper position in Fig. l2 for thereby connecting thepressure ports with the ports 19 and causing a flow of fluid from theconduit 1| to the. conduit 85, and therefore the upper end of thecylinder 51 for actuating the piston 58 downwardly together with theparts connected therewith. The fluid beneath the piston 58 is at thistime being exhausted by way of pipe or conduit 98 to the ports 8| and 83to the pipes or conduits 98 and 91 to the sump or tank 88. As was notedabove, this movement of the piston and parts connected therewith is at arapid rate in a downward direction or toward the work.

The rapid downward or advance movement of the carrier continues untilthe drill or tool is about to strike the work, whereupon this movementis changed to a relatively'slcw feed rate of movement. In order toaccomplish this, the tool carrier 42 is provided therein with a T-shaped slot |01, see Fig. 9, -which extends the length of the carrierand hassecured therein at its upper end a bracket or arm |08, and at itslower end a bracket or arm |09, see Fig. 1'7. Carried by the brackets orarms |08 and |09 is a rod or bar ||0, shown in the Vdrawings as ofanguiar cross section. Mounted on this rod is the cumulative rapidtraverse stop -dog which, as seen in Figs. 8 and 22, is provided with acam shaped nose ||2 on one side of the rod H0, and with a circular boss||3 on the other side thereof. The boss ||3 is hollow to accommodate afriction shoe ||4 backed up by a spring I5 whose tension may be adjustedby screw H6. The cam nose provides an inclined cam face |I1 forengagement with aiiipper dog ||8. The flipper dog H8, as seen in'Figs. 8and 18, is secured to the outer end voi' a stud |I9 oscillatablyjournaled in the tool head plate 18. per dog ||8 is provided with anotch |20 receiving the ballv end of a projection |2| extending from thelever |0|.

From this, it will be seen that the cumulative rapid traverse stop dogis adjustably positioned on the rod ||0 to engage the flipper dog |I8 atthe point where the drill or tool is about to engage the Work. Theoscillation of the flipper dog IIB in a counterclockwise direction, asseen in Fig. 8, actuates the lever in a clockwise direction, which,through the shaft or'stud |02 and arm |04, shifts the valve member to aposition for cutting ofi' the flow of the exhaust fluid through the pipeor conduit 96 and therefore the unrestricted port 8|. This flow isdirected, instead, from the pipe or conduit 96 to the feed determiningvalve, indicated in general in Fig. 24 by the reference numeral |22.

This feed determining valve |22 is shown structurally in Fig. 14, andcomprises la valve The iiipmeer hammam the mr nde or end or valve block13.as shown in dotted lines in Fig. 9. 'I'he valve",l block |23 isprovidedl therethrough with apair of'bores |24 and |23. one end of whichare closed by .a plate |23, while the other ends are in communicationwith a chamber |21. This chamber |21 is in turn closed by 8 plate |28secured to the block |23. Disposed in the valve block bore |24 is avalve member |23 having an inclined groove |33 formed around one. sidethereof. 'I'he valve member is provided adjacent thereto with anenlarged threaded portion |3| threaded into an aperture |32 formedthroughy the closure plate |23. Projecting from the threaded portion |3|is the valve stem |33, hav'- ing its end provided with a portion toreceive a suitable wrench, key or the like whereby the valve may beturned to eifect its adjustment through its enlarged threaded portion|3I.

The most shallow portion of the groove |30 is adjacent to the chamber|21 and determines the rate of flow from this chamber. From this, itwill be seen that the greater the depth of the groove |30, which is incommunication with the chamber |21, the faster the flow fromthis-chamber, and that the position of this groove with respect to thechamber |21. is determined by the' adjustment of the-threaded portion|3| on the valve stem |23 and therefore the rate of ilow of the fluidand the rate of feed of the drill or tool'. This chamber |21 is showndiagrammatically in Fig. 24 as a port |21' to which is connected one endof a pipe or conduit |34 which has its other end connected with the pipeor conduit 98 from the lower 'end of the cylinder 31.

l The valve block |23 is shown as provided with a port |33 between thevalve block bores |24 and |23. 'I'his port |33 is diagrammaticallyillustrated in Fig. 24 as a pipe or conduit |38 connecting the valvebore |24 ahead of the valve member |30 with the bore |28 which containsthe balance valve mechanism, indicated in general by the referencenumeral |00.

The balance valve mechanism is illustrated structurally in Fig. 14, andcomprises a valve member |31 having reduced stem portions |33 and |39 atopposite ends thereof, together with a reduced central portion orcannelure |40. This reduced portion or cannelure controls the flowthrough a port, shown in Fig. 24 by the reference character 4|, withwhich is connected the pipe or conduit 99. 'I'he valve block |23 isshown as having a second port |42 connecting the valve bores |24 and|23, this port being diagrammatically shown as a conduit |43 in' Fig.24, and connects the space ahead of the valve member |29 with thev spaceahead of the valve member |31. The space ahead of the valve member |31,and including the reduced portion |39, includes a spring |44 which-surrounds the said reduced valve portioni 39 and abuts against theclosure plate |28 for urging the valve member |31 to the right, as seenin Fig. 14, or downwardly as seen in Fig. 24, maintaining the port |4|normally open. As will be seen in Fig. 14, the fluid chamber |21 is atall timesvin communication with the end of the valve member |31, andthis chamber is illustrated in Fig. 24 by means of a port |21" withwhich is connected one end of a pipe or conduit |43 which has its otherend connected with the pipe or conduit 33.

, 'I'he operation of the balance valve mechanism is well understood, itspurpose being to maintain a constant flow of fluid through the systemwhen the tool vis -being actuated through. a slow or .feeding cycle...This now from the exhaust pipe or conduit 83 from the cylinder 31 is byway of the pipes orconduits |34 and |43 to the chamber |21 where it actson the balance valve |31 for actuating it against .the resistance` ofspring |44k andl flowing through the groove |30. The flow through thegroove |fis through the ports |33 and |42 respectively and pipe orconduits |33 and |43. The flow through the port |42 or pipe or conduit`|43 combines-with the yieldable urge of the spring |34 for shifting thevalve against the pressure in chamber |21 and therefore opening the port|4| an amount equal to the balance in pressure at the two ends of thevalve as determined by the adjustment of the valve member |29. This flowthrough the port |4| is into the pipe or conduit 88to the main controlvalve mechanism 12 where it is connected with the pipes or conduits 88and 91. and the sump or tank 88.

The slow feeding movement of the tool continues until the tool carrieris reversed for withdrawing the tool from the work. 'I'he reversal ofthe tool carrier maybe accomplished through either of twoinstrumentalities, either after a definite amount of slow feed has-takenplace, or when the torque on the drill reaches a point near the safetorque load on the drill. In order to reverse the tool carrier andwithdraw the drill from the work after a pre-determined amount ofdrilling has taken place, the following mechanism is employed.

Mounted on the dog rod or bar H0, as seen in Figs. 8, 20 and 22, is aslow feed dog |48 having projecting from one side thereof an arm |41into which is threaded a dog screw |48 having a nose |49. The dog screw|49 is locked into adjusted position by lock nut |30. The adjustment ofthe dog screw |48, and the distance between the ends oi its nose |49 andthe cam nose ||2 of the -cumulative rapid traverse dog ill, determinesthe amount of drilling or the amount of slow feed movement imparted tothe tool carrier. 'I'his feed dog |48 is loosely mounted on the dog rodH0 and is connected thereto by means of a pawl |3| disposed in a slot|32 formed in the dog |48 and pivotly connected by means of pivot |33.The upper end of the pawl |3| has projecting therefrom a pin |34 towhich is connected one end of a spring |33 which has its other endconnected with a second pin |38 projecting from the dog |48, see Fig,19. This spring maintains the pointed nose |31 of the pawl 3| inengagement with ratchet teeth |38 formed on the inner face of the dogrod-H0. From the foregoing, it will be seen that even though the feeddog |48 is loosely or slidably mounted on the dog rod H0, it ispositively and mechanically connected therewith. The feed dog |48 ismaintained in definite spaced relation with the cumulative rapidtraverse dog by means of a spring |88 disposed around the dog rod ||0and abutting at opposite ends with said dogs. In order to maintain saiddogs in spaced relation with one another, use is made of a tie rod orbolt |89 which has its lower end threaded into the rapid traverse dogand its upper end passing through a plane perforation in the said dogwith a head at theupper end of the tie rod or bolt |39 engaging theupper surface of feed dog |48.

'I'he nose |49 of the dog screw |48 engages the upper end of a slide`|8| adapted-to slide against the face |82 of the plate 18 of the toolhead 38. Th'e slide |8| is retained in position by a flange |83projecting from a bracket |84 secured to the head plate 16. This slide|61 is provided intermediate its ends with rack teeth |85 meshing with asegmental gear |86, rotatably mounted on the bushing |03 carried by thetool head plate 18.

The segmental gear |66 Ahas projecting rearwardly therefrom an arm |61provided at its rear end with a circular head |68 contacting on oppositesides thereof with valve stems |88 and |10. The valve stems |68 and |10are associated with valve mechanisms which operate pistons for shiftingthe main control valve member 88, and these valve members arerespectively shown diagrammatically in Fig. 24 where they arerespectively indicated in general by the reierence characters |1| and|12.

The valve mechanism |1| is illustrated structurally in Figs. 13 and 15and comprises a valve member |18 integral with the valve stem |68 havinga reduced portion or cannelure |14 intermediate the ends thereof. Thevalve member |18 is mounted in a bore in the valve block 16, which isprovided with three ports |15, |18 and |11. The valve member |18 isadapted, when in the position shown, to connect the ports |16 and |11,and when in its second position, to cut of! the port |11 and connect theports |18 and |15. The valve is shifted to the position shown by meansof a spring |18 disposed in a counterbore in the upper end ofthe valvemember, having its other end seated in a counterbore in a plug |19secured in the upper end of the valve bore. It should be noted at thistime that the plug |19 is of a slightly greater diameter than the valvemember |18, thereby providing a shoulder |80 against which an enlargedcollar portion of the valve member |13 engages to limit the movement ofthe valve member by the spring |18. As seen in Fig. 24, the port |11 hasconnected therewith one end of a branch pressure pipe or conduit |8|`which extends from the main pressure pipe or conduit 1|, while the port|15 has connected v 'therewith one end of a drain pipe or conduit |82,

which terminates at the sump or tank 68. The remaining port |16 isillustrated in Fig. 24 as a pipe or conduit |83 and terminates in acylinder |84. This cylinder is illustrated in Fig. 13 as a bore in whichis mounted a piston |85 which has its lower end in contact with theupper surface of valve shifting arm |04.

From the foregoing it will now be seen that engagement of the dog screw|48 with the slide |6| causes same to actuate the arm |61 and shiftvalve |18, thereby connecting pressure in the pressure line 1| throughthe pipe or conduit |8| and cannelure or reduced portion |14 with thepipe or conduit |83 and cylinder 84, for actuating the valve arm |04 forshifting the main control valve member 85 to its extreme right handposition, as seen in Fig. 24. The shifting of the valve member 85 to itsright hand position connects the pressure in the pipe or conduit 1| withthe pipe or conduit'96, thereby elevating the piston 56, and partsconnected therewith, at a rapid rate. The uid ahead of the piston 56 isexhausted by way of the pipe or conduit 95, main control valve 85 andpipe or conduit 81 to the sump or tank 68.

The foregoing description deals with a step or deep hole drillingmachine, as has been known, that is, with the means for effecting adefinite amount of slow feed drilling prior to reversal. With ths typeof machine, the dogs are usually set to effectually control a smalldrilling stroke, that is, around a quarter of an inch for eachwithdrawal, which means quite a large number of reversals for holes twoor more inches in to the arm |81. and likewise oscillatably mounted onthe stud |88, is an arm |89.having connected to its free end one end ofa spring |90. Theother end of the spring is fastened to the inner end ofan adjusting screw |8| disposed in a bore |92 in the housing 80. Theadjusting screw |9| has threaded on its outer end an adjusting knob ornut |93 which abuts on its inner end against the face of a lug or padprovided on the housing for this purpose. A sheathing and lguide sleeve|84 is likewise secured to the inner end of the screw |8|', and isprevented from rotation'by a dog screw |95.-

It will be noted that the idler tensioning pulley |86 is on the drivingside of the belt, and not on the slack side, as is usual with idlerpulleys. With this construction, the adjustment of the screw |9|, andthe tensioning of the spring |90, places the desired drive tension onthe belt, andl thereby the spindle 40 is driven by the drive sleeve 88.

Just'below the housing 30, the spindle 40 hassplined thereto a shortsleeve |96, to which is secured a pulley |81. Encircling the pulley is abelt |98, which. in turn, is disposed around a second pulley |99, pinnedor otherwise secured to the lower end of a governor spindle 200. The

governor spindle 200 has pinned to its uppcr end a carrier 20|, to whichis pivotly connected arms 202 and 203 having their outer endsrespectively weighted as by balls 204 and 205. 'I'he arms 202 and 203have respectively `pivotly connected therewith, links 206 and 201,respectively having their outer ends connected with'a slider 208,mounted on the governor spindle 200. The slider 208 carries contactplate 209 for contacts 2|0 and 2| I, which contacts are adapted toengage xed contacts 2|2 and 2|8 when the governor spindle 200 is idle orrotating at a speed below that at which centrifugal force will throw outthe balls 204 and 206 and raise the slider 208. The governor spindle200, and parts carried thereby, with the exception of the pulley |99,are encased in a housing 2|4, which is suitably secured to the spindledrive housing at a point to one side of the spindle.

As shown in Fig. 24, the movable contacts 2|0 and 2 have -respectivelyconnected therewith the power lines 2|5 and 2|6 of an electrical supply,while the xedcontacts 2|2 and 2| 3 are respectively connected with theopposite ends of the windings of a'solenoid 2 i 1.

The solenoid 2 I 1, as seen in Fig. 8, is secured to the lower end ofthe tool head plate 16, and has the core 2|8 projecting therefrom. Theupper end of the core 2|8 is plvotlyconnected at 2|9 with a link 220.The upper end of the link 220 is pivotly connected at 22| with anextension 222 of the lever |0|.

In the operation of this governor controlled feed stopping mechanism,the tensioning pulley |86 is adjusted to a safe point below the breakagepoint of a drill or other tool while in operation.

This tension is sumcient to permit the drill or other tool to'properlyoperate when thedrive sleeve 38 and spindle 40 are rotating. Therotation of the spindle40 is imparted by means of thebelt |08 to thegovernor spindle 200, thereby rotating the sameand causing the balls 204and 205, through centrifugal action, to swing out and draw the slider208 upwardly, thereby breaking the control between' the movable contacts2|0 and 2|| and the fixed contacts 2| 2 and 2|3. and breaking theelectric pull of the solenoid 2|1. If, during the drilling operation andslow feed of the tool relative to the work, chips or the like areencountered which increase the torque on the drill to a. pointendangering the lsafety of the drill. it slows down, thereby causing aslippage of the driving belt 36 relative to the pulley 31, and adecrease in speed of the drive sleeve 33 and spindle 40. This decreasein spindle speed naturally causes the slowing down of the governorspindle 200, and the weightedl arms 202 and 203 or the balls 204 and 205to drop by gravity to their normal idle position, thereby bringing intoengagement the contacts 2|0 and 2|| with contacts 2|2 and 2|3,completing'an electrical circuit to the solenoid 2|1. The pull of thesolenoid 2|1, on the core 2|0 through the link 2|0, actuates the lever'|0|, and though its connection with the valve member 85 shifts same toitsretracting position, which is of course to its extreme right handposition as seen in Fig. 24. As was noted above, this position of thevalve member 85 effects the rapid retractionof the spindle carrier andparts carried thereby.

From the foregoing, it will now be appreciated that the tool carrier,and parts carried thereby, may be -retracted from their operativeposition only when necessary, instead of after every quarter inch ofdrilling, as was the practice in the past. In order, however, to besafe. and clear the hole of loose chips periodically, use may also bemade of the feed stop dog |46, which would be set to operate only aftereach inch or more of hole had been drilled, and thereby again materiallycut down on the idle time ofk machines.

Instead of the direct connection between the spindle and governorv byway of the belt |08, above described, use may be made of a frictionclutch mechanism, such as, for example. is shown in Figs. 6 and '1. Inthe construction shown in these figures. the driving sleeve 38 is notkeyed or splined to the spindle 40, but, instead, is secured, as byscrew threads 223, to a sleeve 224, which carries at its lower end aange 225. This flange 225 forms a clutch member and contacts with aclutch facing 226, which, in turn, contacts with a second clutch memberor ilange 221. This second clutch member 221 has a sleeve 228 projectingupwardly therefrom, and is provided at its upper end with keys 220 toenter the splines in the spindle 40. In order words, with theconstruction just described, the friction clutch 225v 221 is, in effect,interposed between the spindle 40 and' its driving mechanism, includingthe pulley 31 and sleeve 38.v With this .type of construction, it isdesired that the tension on the .belt be at all times the drivingtension, whereby. the slack'side of the belt 36 has contacting therewiththe idler tension pulley or roller 230, rotatably mounted at the freeend of an arm 23|, oscillatably mounted on a stud 232 carried by thehousing 30. Also mounted on the stud 232, and connected with the arm23|, is a segmental gear 233, having its teeth enmesh with a worm 234 onthe inner end of a worm shaft 235. The worm shaft 235 is rotatablyjournaled in suitable bearings -provided by the housing 30, and whichhas secured to-its projecting free end a knob 236.

The tension on the friction clutch 225-221 is adjustable by means of acup-shaped nut 231, threaded into the lower end of a housing member 230.Disposed within the cup is a coiled spring 230 which abuts on its lowerend the adjusting nut 231, and on its upper end with an anti-frictionthrust bearing 240, which is carried by the friction clutch member 221and acts through this` thrust bearing `to force the members intoengagement with one another. The housing member 238 cooperate'swith asecond housing member 24| to completely enclose the friction clutch andparts associated therewith, and this housing member is suitably securedto the spindle housing 30 to maintain the parts in operative relation.The clutch member 221 is provided on its periphery with clutch teeth 242which mesh with a pinion 243 secured to the governor spindle 200.

lThe governor mechanism operated by the spindle 200 is, in the presentinstant, identical with that above described, the only difference beingthat, instead of a pulley |00 on the spindle, pinion 243 is substitutedtherefor, and since the performance inl operation of this governor isidentical with that'above described, no further description thereof isdeemed necessary.

The rapid retraction of the spindle carrier and parts associatedtherewith continues until the carrier is reversed. The means andmechanism disclosed in the drawings for eiiecting this reversal includesan arm 244, secured to the lower end of the dog rod H0. The arm 244 hasupstanding from its free end an abutment pin 245 adapted to engage thelower end of a pin 248, illustrated most clearly in Figs. 8 and 23. 'Ihepin 246 is mounted in a cylindrical portion or housing 241, at the endof an arm 248 pinned or otherwise secured to an oscillatable rod 240.The rod 240 is journaled for oscillation at its upper end in a bracket250 carried by the tool head plate 16, and is further journaled at itslower end in the bracket |64, likewise carried by the tool head plate10. As will beseen from Fig. 23, the housing 241 is provided at itslower end with a shoulder 25| on which rests an enlarged collar 252 onthe pin 246. A coil spring 253 surrounds the pin 246 and abuts with thecollar 252 for maintaining the pin in its normal lower position. Thisnormal position of the pin is in line with -the pin 245 and the valveslide |6|, which it engages during the upward movement of the spindlecarrier for thereby upwardly shifting the slide |5|,asseeninFig.22.

This upward movement of the valve slide |6|, through its rack teeth `4|65, oscillates the arm |61 for shifting the valve stem |10 of valvemechanism |12. above, is shown diagrammatically in Fig. 24 andstructurally in Fig. 13, and is substantially identical with the valvemechanism |1|. The valve stem |10, therefore, has connected therewith avalve member 254v having intermediate its ends a reduced portion orcannelure 255. lBelow the connelure 255, the valve stem 254 is providedwith a counterbore in which is set one end of a coil spring 256, whichhas its other end seated in the counterbore ofa plug 251 in the end ofthe bore in the valve block 32 which accommodates the valve 254. Thevalve member 254 is provided with a flange 250 to engage a shoulder 2::to limit the movement thereof -by the spring 2 The valve mechanism |12,as noted i As shown in Fig. 24, the reduced portion or cann/elure 255normally connects ports 2 80 and 28|, and when operated by the arm |81,connects the ports 28| and 282. The ports- 282 have connected therewithone end of a branch pressure pipe or conduit 283, while the .ports 280have connected therewith one end of a pipe or conduit 284,v whichterminate in the sump or tank 88. The remaining ports. 28| haveconnected therewith one end of a pipe or conduit 285, terminating at itsother end in a cylinder 288. While the connection between the ports ofthe valve mechanism |12 is illustrated, in Fig. 24, as pipes orconduits, they are in fact merely cross-drilled ports in the valve block82'.

The cylinder 288 is in effect a cylindrical bore in valve block 82,which has disposed therein a piston 281, engaging the undersurface ofthe valve shifter arm |04. The operation of the pitson 281 shifts themain control valve 85 to its extreme left hand position, therebyconnecting the pressure in the pipe or conduit 85 and the top of thecylinder 51 for actuating the piston 58 therein downwardly at a rapidrate. The-uid ahead of the piston 58 is forced through the pipe orvconduit 88, to the main control valve 85, where it is connected withthe pipes or conduits 81 and 88 and the sump or tank 88, thereby rapidlyadvancing the tool to the work.

From the foregoing, it will now be noted that the dog 244, through itspin 245 and the intermediate pin 248, reverses the movement 'of the toolcarrier. It should be noted at this time that this reversal took placeat a point short of the initial position of the tool carrier, vand fromwhich initial position the carrier was actuated by the manual` operationof the lever It should also be noted that the frictional connection ofthe cumulative stop dog causes the feed dog to move upwardly withl thecarrier and is therefore now positioned on the dog rod or bar 0 at apoint where the previous slow movement or drilling of the work stopped.

During this upward movement of the carrier, a cam plate 288, carried bythe tool head and having a cam 288 thereon, engages a lug or knob 210 onthe feed latch |8| for actuating same about its pivotal connection |53and clisengaging the nose |51 from the rack teeth |58. Upon thedisconnection of the feed dog |48 from the dog bar ||0, the spring |58,compressed during the previous slow feed movement of the carrier,expands for separating the cumulative and feed dogs an amount determinedby the conecting pin or bolt |59 and again positioning the feed dog topermit its subsequent operation. It will be appreciated of course, thatthis feed dog may not have operated to reverse the carrier, which mayhave been accomplished by the governor controlled mechanism, but,nevertheless, the feed dog l was actuated toward the cumulative stop dogwhose movement was arrested by engaging the top face or surface 21| ofthe bracket |84 immediately after the operation of the -flipper ||8.

The rapid downward movement of the carrier, and parts carried thereby,continues until the cumulative stop dog, through its cam ||1 againshifts the flipper I8 for slowing down the movement of the carrier to afeeding rate. The feed then continues until the drilling distance, asestablished by the spacing of the dog screw nose |48 from the cumulativestop dog I, has taken place, or until the torque on the drill reachesthe. point for substantially slowing down' the rotation of the governorspindle, so that its switch 2|0-2I2 closes, whereupon the carrier isreversed to vretract the tool from the work and effect a clearing of thechips from the jhole being bored.

This cycle of operation is repeated continuously until the hole iscompletely bored through, whereupon the parts are returned to theirinitial -position and the movement of the tool carrier stopped.

This mechanism for returning the carrier to its initial position, andstopping the mechanism, comprises a cam dog 212, see Fig. 1, which has acam face 213 and is adjustably positioned in the T-slot |01 in thecarrier. This dog 212 is adjusted to the point where it comes intooperation after the work has been completely bored, and is adapted toengage the end 214, see Fig. 21.l of a short rack 215 mounted fortransverse movement in the bracket |84. The rack 215 has its teeth 218meshed with a pinion 211, keyed or otherwise secured to the rod 240,which, as noted above, carries at its lower end the arm 248. 'I'his rod248, in addition, has secured thereto a resetting member 218. see Figs.8 and 19, having a lug 218 adapted to overlie a lug 280 projecting fromthe side of the cumulative stop dog When the tool of the carrier hascompletely bored the hole being drilled, the cam dog 212 shifts the rack215 outwardly, as seen in Fig. 21, or to the right, as seen in Fig. 1,thereby oscillating the rod 248. This oscillation of the rod 248 carrieswith it the arm 248 and removes the intermediate pin 248, carried by itsouter end, from the path of movement of the dog pin 245so that theupward movement of the cam slide |8| cannot be effected. This then.permits the carrier to travel beyond the point -where it is nor- 4mally reversed by the dog 244. In order to stop the carrier at its upperlimit of movement, it has -projecting from it, see Fig. 22, a pin 28|,which engages the projecting end 202 of an arm 283 keyed or otherwisesecured to the inner end of the flipper dog stud or shaft |18, as seenin Fig. 18. This stud or flipper dog shaft ||8 is connected, through theseat andr lug |20 and |2|. with the lever |0|, and therefore the valvemember 85, for shifting the valve to its stop or neutral position. Inorder to initiate further operation of the machine, it is necessary toshift the valve to position by the lever |0|.

4The oscillation `of the rod 248, as above described, also shifts theresetting 'member 218 to the position to cause the projection 218 tooverlie the cumulative stop dog lug 280 and thereby hold the said dogrelative to the dog bar ||0 during this final upward movement of thecarrier, and thereby positioning the cumulative dog to its initialposition for a subsequent operation of the machine. The positioning ofthe cumulative stop dog through its connection or pin |59,correspondingly positions the feed dog |46 on the dog bar. The operationof the handle or lever |0|,

for starting up the machine. effects the oscillation of the rod 248. soas to free the cumulative In order to hold the rod 248 in either of itstwo operative positions, it has keyed or otherwise secured to it, at apoint below the bracket |84. a

with a spring pressed detent 288.

`tion of the work and a rapid movement from the work. The control ofthis cycle is dependent largely on the torque on the drill or toolduring its operation, which control may be supplemented by means forperiodically clearing the hole of chips toinsure accuracy in drilling,and ultimate safety of the drill. It will be 'appreciated that the idletime oi' machines as heretofore known and used has been greatly reduced,while the mechanism is held to ultimate simplicity when considering thenecessarily involved circuit.

What is claimed is:

l. In a drilling machine of the class described, the combination of atool carrier, means for rotating the tool, means for reversely actuatingthe carrier and tool relative to the work. a speed control governorconnected with the tool to have imparted thereto the rotations of thetool, and means operable by said governor upon slowing down in rotationof the toolfor reversing the direction. of movement o! the tool relativeto the.

4with said tool carrier actuating means for reversing the said actuatingmeans, means for shifting the control member to a position to cause thetool carrier to move toward the work, and means l"operable by theslowing down of the governor for actuating the control member to aAposition for withdrawing the tool from the work.

3. In a drilling 1machine of the class described,

the combination ot a tool carrier for rotatably supporting a drill orother tool, a governor connected with said tool i'or having therotations of the tool imparted thereto, means Yfor actuating means forshifting the control valve to a position for actuating the toolcarriertoward the work, and means operable lby the governor for shitting thecontrol valve upon slowing down of the tool spindle to a point forretracting the tool carrier from the work.

5. In a drilling machine oi the class described, the combination of atool carrier, a tool spindle rotatably mounted on the carrier, ahydraulic piston and cylinder mechanism for actuating the tool carriertoward 'and from the work, a hydraulic circuit for effecting theoperation of the piston and cylinder mechanism and including amulti-position control valve, a speed controlling governor connectedwith the spindle to have imparted to it the rotations of the toolspindle, means for shifting thecontrol 'valve to a position foractuating the tool carrier toward the work, means operable bythegovernor for shifting the control valve upon slowing down oi' the toolspindle to a point for retracting the tool carrier from the work, saidtool carrier having a definite stroke length and means operableintermediate the ends of the carrier stroke length for shifting thecontrol valve to its position for retracting the tool carrier from thework.

l6. In a drilling machine of the class described. the combination of atool carrier mounted for reciprocating lmovement toward and from a workpiece, a tool spindle rotatably supported by the tool carrier, means forrotating the spindle and a tool carried thereby, a piston and cylindermechanism one of whichl is movable and connected with the carrier foreiecting its reciprocation in reversed directions a hydraulic circuitfor eiecting and controlling the operation o! the movable member of thepiston and cylinder mechanism including a control valve, manual meansfor shifting the control valve to a posi--' tion for actuating the toolcarrier toward the work, electro-magnetic means for shifting the thetool carrier and tool toward the work while the tool is rotating, acontrol member asso-v ciated with said tool carrier .actuating means forreversing the said actuating means, means for shifting the controlmember to a position to cause the tool carrier to move toward the work,and means operable by the slowingfJ down of the governor for actuatingthe control member to a position for withdrawing the tool from the work,and additional means associated with the tool carrier for actuating thecontroll member to a position for withdrawing the tool from the work.

4. In a drilling machine of the class described, the combination of atool carrier, a tool spindle rotatably mountedon the carrier, ahydraulic piston and cylinder mechanism for actuating the tool carrier vtoward and from the work. a hydraulic circuit kfor effecting theoperation of the piston and cylinder mechanism and Aincluding amulti-position control valve, a speed controlling governor connectedwith the spindle to have lm parted to it the rotations of the toolspindle,

valve to a position for actuatingv the tool carrier from the work, and acontrol switch for saidv electro-magnetic valve shifting means operableupon decrease in rotation of the tool spindle and tool carried thereby.

7. In a drilling machine lot the class described, the combination of atool carrier mounted for reciprocating movement. toward and from a workpiece, a tool spindle rotatably supported by the too'l carrier, meansfor rotating the spindle and a tool carried thereby, a piston andcylinder mechanism one or which ismovable and connected with the carrierfor eilecting its reciprocation in reversed directions, av hydrauliccircuit for effecting and controlling the operation of the movablemember of the piston and cylinder mechanism including a control valve,manual means for shitting the control valve to a position for actuatingthe tool carrier toward the work, electro-magnetic means for shiftingthe valve to a position for actuating the toolcarrier from the work, anda control switch for said electromagnetic valve shifting means operableyupon decrease in rotation of the tool spindle and tool carried thereby,and including a governor connected with the spindle and having impartedthe feto the rotations of the spindle.

8. In a drilling machine of the class described. the combination of atool carrier mounted for reciprocating movement toward and from a workpiece, a tool spindle rotatably supported by the tool carrier, means forrotatingthe spindle and a.

tool carried thereby. a piston and cylinder mechwith the carrier foreffecting its reciprocation in reversed directions, a hydraulic circuitfor effect ing and controlling the operation of the movable member ofthe piston. and cylinder mechanism including a control valve, manualmeans for shifting the control valve to a position for actuating thetool carrier toward the work, electromagnetic 'means for shifting thevalve to a position for actuating the tool carrier from the work, and acontrol switch for said electro-magnetic valve shifting means operableupon decrease in rotation of the, tool spindle and tool carriec thereby,and additional means for shifting the control vvalve to a position foractuating the tool carrier from the work.

9. In a drilling machine of the class described, the combination of atool carrier. a tool spindle mounted for rotation in the carrier, abelt-drive for effecting the rotation of the spindle, means f ortensioning the belt to a point below the safe torque limit of the tool,means for actuating the tool carrier toward a .work piece during therota- 'tion of the tool including a control member, a

governor connected with the tool spindle to have imparted thereto therotation of the tool spindle, and means operable upon slowing down ofthe governor for actuating the control member to reverse the directionof movement of the tool car rier when the torque on the tool exceeds theestablished driving tension on the belt.

' 10. In a drilling machine of the class described, the combination of atool carrier, a tool spindle mounted for rotation in the carrier, a beltdrive for effecting the rotation of the spindle, means for tensioningthe belt to a point below the safe torque limit of the tool, means foractuating the tool carrier toward a work piece during the rotation ofthe tool including a control member, a governor connected with the toolspindle to have imparted thereto the rotation of the tool spindle, andmeans operable upon slowing down of the governor for actuating' thecontrol member to reverse the direction of movement of the tool carrierwhen the torque on the tool exceeds the established driving tension onthe belt, said governor operated means including a switch operatedthereby and controlling an electro-magnetic control member actuator.'l'1 11. In a drilling machine of the class described, the combination ofa tool spindle, means for supporting said tool spindle for translationtoward and from a work piece, means including a friction clutch forrotating the spindle during its translation, means for establishing theslipping point of the friction clutch just below the critical torquebreaking point of the drill, a control member for reversing thetranslation of the tool cartranslation of the carrier, means forshifting the valve to effect a rapid translation of the carrier towardthe work, cumulative stop means associated with the carrier for shiftingthe valve to change the rate of translation of the carrier, a.

' governor operatively connected with the spindle to have impartedthereto the rotations of the spindle, means associated with the spindlerotating means for determining the ultimate effective torque on thespindle which is at a point below the torque breaking point of thedrill, means operable by the governor upon'slowing down of the spindleeffected by the torque on the drill reaching the point of torqueadjustment on the spindle driving means for shifting the valve to aposition for translating the carrier away from the work, and means forshiftingthe valve to its position for causing the translation ofthecartranslatable carrier for said spindle, means for rotating the spindleduring its translation, a hydraulically actuated piston for translatingthe carrier and spindle, a multi-position control valve for controllingthe rate and direction o'i' translation of the carrier, means forshifting the valve to effect a rapid translation of the carrier towardthe work, cumulative stop means associated withthe carrier for shiftingthe valve to change the rate of translation of the carrier, a governoroperatively connected with the spindle to have imparted thereto therotations o1" the spindle, means associated with the spindle rotatingmeans for determining the ultimate effectivetorque on the spindle whichis at a point below the torque breaking point of the drill, .meansoperable by the governor upon slowing down of the spindle effected bythe torque on the drill reaching the point of torque adjustment on thespindle driving means for shifting the valve to a position fortranslating the carrier away from the work, and means for shifting thevalve to its position for causing the translation of the carrier towardthe work, said governor operable means including a switch operated bythe governor and connected with electro-magnetic valve shifting means.

14. In a step drilling machine of the class described, the combinationof a tool spindle, aV

t the work, cumulative stop means associated with the carrier forshifting the valve to change the rate of translation of the carrier, agovernor adjacent the spindle, a direct belt connection between thespindle and governor whereby the rotations of the spindle are impartedto the governor, means associated with the spindle rotating means fordetermining the ultimate effective torque on the spindle which is at apoint below the torque breaking point of the drill, means operable bythe governor upon slowing down of the spindle.

effected by the torque on the drill reaching the point of torqueadjustment on the spindle driving means for shifting the valve toaposition for translating the carrier away from the work, and means forshiftingr the valve to its position for causing the translation of thecarrier toward the work, said governor operable means including a switchoperated by the governor and connected with electro-magnetic valveshifting means.

15. In a step drilling machine oi the class described, the combinationof a tool spindle, a translatable carrier for saidspindle. means for`rotating the spindle during its translation, a hydraulically actuatedpiston for translating the carrier and spindle, a multi-position controlvalve for controlling the rate and direction of translation of thecarrier, means for shiftingthe valve to effect a rapid translation ofthe carrier toward the work, cumulative stop means associated with thecarrier for shifting the valve to change the rate of translation of thecarrier, a governor adjacent the spindle, a Idirect gear connectionbetween the spindle and governor whereby the rotations oi the spindleare imparted to the governor, means associated with the spindle rotatingmeans for determining the ultimate eilective 4torque on the spindlewhich is at a point .below the torque breaking point of the drill, meansoperable by the governor upon slowing down of the spindle effected bythe torque on the drill reaching the point of torque adjustment on thespindle driving means for shifting the valve to a position for Ciltranslating the carrier away from the work, and

means for shifting the valve to its position for lcausing thetranslation of the carrier toward the work, said governor operable meansincluding a switch operatedby the governor and connected withelectro-magnetic valve shifting means.

16. In a step drilling machine of the class described, the combinationof a Y tool spindle, a translatable Vcarrier for said spindle, means forrotating the spindle during its translation, a hydraulically actuatedpiston for translating the carrier and spindle, a multi-position controlvalve for controlling the rate and direction of translation of thecarrier, means for shifting the valve to eiect a rapid translation ofthe carrier toward the work; cumulative stop means associated with thecarrier for shifting the valve to change the rate of translation of thecarrier, a governor operatively connected with the spindle to haveimparted thereto the rotations of the spindle, means associated with thespindle rotating means for determining the ultimate effective torque onthe spindle which is ata point below the torque breaking point of thedrill, means operable by the -governor upon slowing down of the spindleeffected by the torque on the drill reaching the point of torqueadjustment on the spindle driving means for shifting the valve to aposition for translating the carrier away from the work, means forshifting the valve to its position for work, and means associated withthe carrier for shifting the valve lto a position for translating thecarrier away from the work.

`1'7. In a step drilling machine of the class described, the combinationof a tool spindle, a translatable carrier for said spindle, meansforrotating the spindle during its translation, a hydraulically actuatedpiston for translating the carrier and spindle, a multi-position controlvalve for controlling the rate and 'direction of translation of thecarrier, means for shifting the valve toeifect a rapid translation ofthecarrier toward the work, cumulative stop means associated with thecarrier for shifting the valve to change the rate of translation of thecarrier. a governor operatively connected with the spindle to haveimparted thereto the rotations of the spindle, means associated with thespindle rotating means for determining the ultimate effective torque onthe spindle which is at avpoint below the torque breaking point of thedrill, means operable by the governor upon slowing down' of the spindleeffected by the torque on the drill reaching the point of torqueadjustment on the spindle driving causing the translation of the carriertoward the Y means for shifting the valve to a position for translatingthe carrier away from .the work,

means for shifting thevalve to its position for causing the translationof the carrier toward the work, and means associated with the carrierfor shifting the valve to a position for stopping the translation of thecarrier.

18. In a step drilling machine of the class described, the combinationof a tool spindle, a translatable carrier for said spindle, means forrotating the spindle during its translation, a hydraulically actuatedpiston for translating the carrier and spindle, a multi-position controlvalve for controlling the rate and direction of translation ofthecarrier, means for shifting the valve to effect a rapid translation ofthe carrier toward the work, cumulative stop means associated with thecarrier for shifting the valve to change the rate of translation of thecarrier, a governor operatively connected with the spindle to haveimparted thereto the rotations of the spindle,

means associated with the spindle rotating means for determining theultimate eiective torque on the spindle which is at a point below thetorque breaking point of the drill, means operable by the governor uponslowing down of the spindle effected by the torque on the drill reachingthe point of torque adjustment on the spindle driving means for shiftingthe valve to a position for translating the carrier away from the work,means for shifting the valve to its position .for causing thetranslation of the carrier toward the work, means associated with thecarrier for shifting the valve to a position for translating the carrieraway from the work, and means as-` sociated with the carrier forshifting the valve to a position for stopping the translation of thecarrier.

19.7111 a step drilling machine of the class described, the combinationof a spindle, means for rotating the spindle, means for establishing theeective driving 'torque in said spindle rotating means, a translatablecarrier rotatably supporting the spindle during its translation, a hythecarrier at a slow rate toward the work, a`

speed operated governor connected with the spindle to have impartedthereto the rotations of the spindle, means operated by the governorupon slowing down thereof due to the torque on the drill exceeding theefl'ective driving torque of the spindle. driving means for positioningthe valve to actuate the carrier at a rapid rate from the work, dogmeans on the carrier for positioning the valve to actuate the carrier ata rapid rate `from the work, dog means on the carrier for positioningthe valve for rapidly advancing the carrier toward the work, and meansfor positioning the valve to stop further translation of the carrier.

GEORGE K. McKEE.

